KR20200046107A - Galvanometer calibration system and method - Google Patents

Abstract

The present invention changes the swing angle of the galvanometer in the galvanometer scanning system, so that the optical axis of the galvanometer moves along the first horizontal direction and the second horizontal direction, respectively, and a plurality of fields in the field corresponding to the galvanometer Forming an optical spot and measuring and recording the positions of the plurality of optical spots through an optical spot position measuring device; Step S2 of acquiring an error parameter in a current galvanometer field by substituting data measured by the light spot position measuring device into an overlay model in a field; Calculating an error amount in the galvanometer field to be compensated according to an error parameter in the current galvanometer field, wherein the error amount in the galvanometer field includes a first horizontal direction error amount and a second horizontal direction error amount. S3; And, through the galvanometer controller, correct for the galvanometer scanning system according to the first horizontal error amount and the second horizontal error amount obtained in step S3, and the corrected galvanometer scanning system is restarted. Scanning to control the re-forming of a plurality of light spots, and detecting and recognizing the precision of the re-formed plurality of light spots to repeat steps S1 to S3 if the precision is not satisfied; Provided is a galvanometer correction system and method implemented through step S4 in which the repeat step is stopped when the precision is satisfied to complete error correction in the field.

Description

Galvanometer calibration system and method

The present invention relates to the field of scanning devices, and to a galvanometer correction system and method.

The galvanometer undergoes a constant calibration before and after use, and then obtains a constant compensation amount data, thereby enabling more precise scanning during use.

In the existing calibration method, manual calibration was used, and thus an error is likely to occur in the manual calibration process, and the correction effect is less.

An object of the present invention is to provide a galvanometer correction system and method for solving the problem of poor correction effect.

In order to solve the above technical problem, the present invention is a galvanometer scanning system including a galvanometer; A galvanometer controller for controlling the movement of the galvanometer to implement a plurality of light spots in a field corresponding to the galvanometer; Gantry; A focusing device for focusing on the light flux emitted through the galvanometer; A detection and sampling system for implementing alignment between an optical spot position measuring device and the galvanometer; And an optical spot position measuring device, wherein the galvanometer scanning system is capable of moving in a first horizontal direction along the gantry and also in a vertical direction along the gantry. have.

Optionally, the galvanometer calibration system further comprises a water cooling system for performing water cooling with the galvanometer scanning system.

Optionally, the light spot position measuring device is a profilometer.

Optionally, the galvanometer correction system further includes a work stage capable of moving along a horizontal second horizontal direction, wherein the second horizontal direction is perpendicular to the first horizontal direction, and the optical spot position is measured. The device is connected to the top or side of the work stage.

Optionally, the work stage is for driving the light spot position measuring device to move to implement measurement for the light spot position.

Optionally, a plurality of the galvanometer scanning systems are installed in the gantry.

Optionally, the galvanometer correction system further comprises a laser device for providing an incident light flux to the galvanometer scanning system.

Optionally, the focusing device is an F-theta lens.

In order to solve the above technical problem, the present invention further provides a galvanometer correction method using the galvanometer correction system, and the method includes the following steps.

In step S1, the swing angle of the galvanometer in the galvanometer scanning system is changed to cause the optical axis of the galvanometer to move along the first horizontal direction and the second horizontal direction, respectively, and in a field corresponding to the galvanometer. A plurality of light spots are formed, and the positions of the plurality of light spots are measured and recorded through an optical spot position measuring device.

In step S2, the data measured by the light spot position measuring device is substituted into the overlay model in the field to obtain an error parameter in the current galvanometer field.

In step S3, an error amount in the galvanometer field to be compensated is calculated according to an error parameter in the current galvanometer field, wherein the amount of errors in the galvanometer field is the first horizontal error amount and the second horizontal error amount. It includes.

As step S4, the galvanometer scanning system corrects and corrects the galvanometer scanning system according to the first horizontal direction error amount and the second horizontal error amount obtained in step S3 through a galvanometer controller. The system controls to re-scan to re-form a plurality of light spots, and also detects and determines the precision for the re-formed plurality of light spots, so that if the precision is not satisfied, steps S1 to S3 are repeated; When the precision is satisfied, the repeating step is stopped to complete error correction in the field.

Optionally, the in-field overlay model in step S2 is as follows.

Δx = Mx · x-Ry · y + Tx

Δy = My · y + Rx · x + Ty

here,

Δx, Δy: represents the deviation between the actual imaging position of the light spot in the horizontal direction and the nominal position in the first horizontal direction and the second horizontal direction;

x, y: represents the nominal position of the light spot set by the galvanometer controller;

Tx, Ty: represents the parallel movement of the actual imaging position of the light spot in the galvanometer field and the nominal position in the first horizontal direction and the second horizontal direction;

Mx, My: represents the magnification of the actual image size of the light spot in the galvanometer field to the nominal image size of the light spot in the first horizontal direction and the second horizontal direction;

Rx, Ry: the actual imaging position and nominal position of the light spot in the galvanometer field indicate rotation in the first horizontal direction and the second horizontal direction;

In the test, a total of n = M × N light spots is measured, M and N are natural numbers, and for n light spots, the overlay model in the field is converted into a matrix form:

이며,

And

Fit by least squares method to get errors Tx, Ty, Mx, My, Rx, Ry in the current galvanometer field.

Optionally, the first horizontal direction error amount and the second horizontal error amount in step S3 include the amount of compensation of the optical axis of the galvanometer at the nominal position of each light spot, and are represented as follows.

DeltaX (y) = Δx-Tx-0.5 · (Rx + Ry) · y

DeltaY (x) = Δy-Ty-0.5 · (Rx + Ry) · x

Optionally, the galvanometer scanning system performs multiple light spot position measurements at each specified measurement position, takes the average value of the plurality of light spot position data and applies it to the calculation in step S3.

Optionally, the method for calibrating the galvanometer further includes the following steps.

As step S5, the position in the field of the optical axis of the galvanometer of the galvanometer scanning system is maintained to remain unchanged, and the galvanometer scanning system performs the first horizontal movement in the gantry, and the galva per stepping The position of the light spot projected each time at each stepping position in the zero coordinate system of the gantry using the light spot position measuring device and projecting the light spot multiple times by the nomometer scanning system x _{i, j} , y _{i, j} is measured, i = 1,2, ..., n is the number of steps, j = 1,2, ... , m is the number of times the light spot is projected at each stepping position.

In step S6, the position of the galvanometer scanning system is maintained to remain unchanged, the optical axis of the galvanometer is performed along the first horizontal direction, and light spot projection in the field is performed at each measurement position, and the light is In the zero coordinate system of the gantry, a horizontal position x ′ _{i, j} , y ′ _{i, j} of each light spot projected at each measurement position is measured using a spot position measurement device, i = 1,2 ,. .., n is the number of measurement positions, and j = 1,2, ... , m is the number of light spots projected at each measurement position.

As step S7, the nominal position of the light spot in step S6 and the nominal position in step S5 are the same, respectively, x_nom _i , y_nom _i , and in step S5 and step S6 all m at each position for the galvanometer scanning system A single exposure was performed, and the average value for the sampling data of the light spot of each part:

을 구하며,

Seeking

Substituting the sampling data into the following formula to perform least square fitting to obtain the galvanometer installation rotation amount k,

In the above formula, b is a constant.

As step S8, through the galvanometer controller, the galvanometer scanning system is corrected according to the amount of rotation of the galvanometer obtained in step S7, and the corrected galvanometer scanning system is re-scanned to detect a plurality of light spots. By controlling to re-form, and detecting and recognizing a plurality of re-formed light spots, repeat steps S5 to S7 if the precision is not satisfied, and stop the repeating step when the precision is satisfied to complete the installation rotation correction do.

Compared with the prior art, the present invention provides a galvanometer correction system and method, and when performing the calibration, the measurement position specified by the galvanometer scanning system (determined by the optical axis position of the galvanometer, as a nominal position) (Understandable) by forming a plurality of light spots in the field corresponding to the measurement position using the deflection angle of the galvanometer, and calculating the relationship between the actual measurement position and the nominal position of the plurality of light spots, The error compensation amount in the field of the galvanometer scanning system is obtained, and after calculating the compensation amount, the accuracy of the compensation amount is verified by substitution calculation, and the present invention also uses a similar measurement, calculation, and calculation process to obtain a galvanometer. Correction is performed for the rotation error of the installation, which not only removes the existing error during calibration, but also determines the amount of compensation after verification. To ensure the province's strong practicality.

1 is a view showing a correction method in the present invention.
2 is a view showing a correction system in the present invention.
3 is a view showing a compensation amount feedback in the present invention.
4 is a diagram showing the dots in step S1 of the galvanometer scanning system of the present invention.
5 is a diagram showing the dots in steps S5 and S6 of the galvanometer scanning system of the present invention.
6 is a structural diagram when the optical spot position measuring device is located at the side of the work stage in the present invention.
7 is a theoretical calculated value of the light spot position deviation in the x direction and the y direction in the embodiment of the present invention.
8 is an optical spot distortion variable obtained by actually measuring the F-theta calculated value in an embodiment of the present invention after introducing it into the compensation amount.
9 is an actual distortion curve after the light spot position is corrected in the embodiment of the present invention.
10 is a view showing a structure in which a plurality of galvanometer scanning systems are connected to a gantry.

Hereinafter, the galvanometer correction system and method provided by the present invention will be described in more detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that, in order to briefly and clearly assist the purpose of the embodiments of the present invention, the drawings use inaccurate proportions using very simplified forms.

The galvanometer is one of the members commonly used in the laser processing process, and can be used in combination with a laser device, an F-theta lens, and the like to implement laser scanning of a workpiece to be processed. The galvanometer has a generally planar surface and is capable of swinging within a certain angular range relative to its central axis, and the action of the galvanometer is, for example, a path in which the laser beam emitted by the laser device is preset. Is to reciprocate along. However, due to factors such as working environment and installation precision, the actual working performance of the galvanometer may not meet the expected requirements, so it is necessary to perform calibration on the galvanometer.

To this end, the present invention presents a galvanometer correction system and method. In one specific embodiment, since the galvanometer used in the laser processing process is described as an example, the light source device is described as a laser device in the following embodiment. , The focusing device will be described as an F-theta lens. However, it will be understood by those skilled in the art that the calibration of the galvanometer may be implemented using other light source devices and / or other focusing devices, and the present invention is not limited thereto.

1 to 3, the galvanometer calibration system according to one specific embodiment includes a galvanometer scanning system 1, a galvanometer controller 2, a laser device 3, and a gantry 4 , F-theta lens (5), detection and sampling system (6) and optical spot position measuring device (7), wherein the F-theta lens (5) is emitted by the galvanometer scanning system (1) For focusing on the luminous flux, the detection and sampling system 6 is for realizing the alignment between the light spot position measuring device 7 and the galvanometer scanning system 1, for example detection and sampling Sampling for the alignment mark position on the substrate bearing by the work stage 9 via the system 6 can obtain the first positional relationship of the light spot position measuring device 7 to the substrate, again detecting and To the galvanometer scanning system 1 of the sampling system 6 A second positional relationship to implement the alignment by obtaining the positional relationship for the galvanometer scanning system (1) of the light spot position measuring device (7) according to (which ryangim base). The galvanometer controller 2 controls the galvanometer scanning system 1 to scan, so that one or a plurality of specified measurement positions (optical axis of the galvanometer) of the galvanometer scanning system 1 It is determined by the position and can be understood as a nominal position) to form one or more light spots using the deflection angle of the light source and the galvanometer emitted by the laser device 3, and scanning the galvanometer The system 1 is installed on the gantry 4, can move in the x direction along the gantry 4, or in the z direction along the gantry 4, where z is the vertical direction. For example, a galvanometer is installed in the gantry 4 in such a way that the central axis extends in the y direction, where the x direction and the y direction are two directions that are perpendicular to each other in a horizontal plane.

The galvanometer correction includes error correction in the galvanometer field and galvanometer installation rotation correction.

Error correction in the galvanometer field includes the following steps.

As step S1, the swing angle of the galvanometer of the galvanometer scanning system 1 is such that the galvanometer optical axis (i.e., the optical axis of the light emitted through the galvanometer) dot sequentially in the x direction and the y direction. That is, the galvanometer optical axis and the xy plane form an intersection so that a plurality of light spots are formed in a field corresponding to the galvanometer, and the light spot position measuring device 7 is a galvanometer scanning system 1 The positions of all light spots generated by are measured and recorded, where, as shown in FIG. 4, scanning is performed in the x direction to obtain a plurality of first corrected light spots 10, and scanning in the y direction results in a plurality of A second corrected light spot 11 is obtained.

As step S2, the position data of the first corrected light spot 10 and the second corrected light spot 11 measured by the position measuring device 7 are substituted into an overlay model in the field, and an error in the field of the current galvanometer Get the parameters.

In step S3, the amount of compensation in the x and y directions of the galvanometer is calculated to compensate for errors in the field of the galvanometer.

As step S4, the galvanometer controller 2 compensates for the galvanometer scanning system 1 according to the amount of compensation in the x-direction and y-direction obtained in step S3, and also after the compensation the galvanometer scanning system ( 1) to re-scan to form a light spot (i.e. repeat step S1), also detect the re-formed light spot and determine the precision (i.e. repeat step S2) to compensate if the precision is not satisfied The amount (that is, repeat step S3) is calculated again. The steps S1 to S3 can be repeated several times until the precision is satisfied, and if it is satisfied, the repeating step is stopped to complete error correction in the field.

Here, the overlay model in the field in step S2 is as follows.

In the above formula,

Δx, Δy: the x-direction and y of the actual imaging position of the light spot in the horizontal direction (ie the position measured by the position measuring device 7) and the nominal position (ie the position set by the galvanometer controller 2) Indicates deviation in direction;

x, y: represents the nominal position of the light spot set by the galvanometer controller;

Tx, Ty: represents the parallel movement between the actual imaging position of the light spot in the galvanometer field and the nominal position in the x and y directions;

Mx, My: represents the magnification of the actual image size of the light spot in the galvanometer field relative to the nominal image size of the light spot in the x and y directions;

Rx, Ry: represents the rotation of the light spot in the galvanometer field with respect to the actual imaging position and nominal positions in the x and y directions;

In the test, total n = M × N light spots are measured, where M and N are natural numbers, and for n light spots, converting (2-1) to matrix form:

이며,

And

Fit by least squares method to get errors Tx, Ty, Mx, My, Rx, Ry in the current galvanometer field.

The compensation amount of the galvanometer in step S3 is as follows, that is, the compensation amount of the optical axis of the galvanometer scanning system at each x and y position is as follows.

In the x-direction and y-direction, the galvanometer scanning system 1 forms a plurality of light spots at the front and rear at each measurement position, and also takes the average value of the position data of the plurality of light spots and applies it to the calculation of step S3. .

The galvanometer installation rotation correction includes the following steps.

As step S5, the position in the field of the optical axis of the galvanometer scanning system 1 is maintained unchanged, that is, the galvanometer is maintained at one fixed swing angle so that the angle of inclination between the optical axis of the galvanometer and the xy plane is unchanged. The galvanometer scanning system 1 performs the x-direction movement in the gantry 4, and the galvanometer scanning system 1 projects the light spot once per stepping, and also the optical spot position measuring device (7) Using the gantry (4) zero coordinate system, measure the position x _{i, j} , y _{i, j} of the light spot generated by projecting once at a single measurement position, where i = 1,2, ... , n is the number of exposure marks, and the number of measurement times is obtained by acquiring a plurality of measurement values at the measurement position using the light spot position measurement device 7 by projecting multiple light spots at each measurement position. And j = 1,2, ... , m. As shown in Fig. 5, dots in the x direction are obtained to obtain a third corrected light spot 12 on a plurality of identical horizontal lines.

As step S6, the position of the galvanometer scanning system 1 is maintained to remain unchanged, and the optical axis of the galvanometer is scanned along the x direction through the swing of the galvanometer, thereby implementing a plurality of light spots in the x direction. And a horizontal position x ′ _{i, j} of each light spot formed by the galvanometer scanning system 1 in the swing process in the gantry 4 zero coordinate system using the light spot position measuring device 7 , y ′ _{i, j} , where i is the number of galvanometers to form light spots at different positions, and j is the number of times measured using the light spot position measuring device 7 at each light spot position. And thus a plurality of fourth corrected light spots 13 are obtained.

As step S7, the nominal position of the light spot in step S6 and the nominal position in step S5 are the same, respectively x_nom _i , y_nom _i , and each measurement position for the galvanometer scanning system 1 in steps S5 and S6 In m spot projection is performed, and the average value for the sampling data of the light spot of each part is:

을 구하며,

Seeking

Substituting the sampling data into the following formula to perform least square fitting to obtain the galvanometer installation rotation amount k,

In the above formula, b is a constant.

As S8, the amount of rotation of the galvanometer installed in step S7 is substituted into the galvanometer controller 2, and used to control the galvanometer scanning system to re-scan to re-form the light spot, and also re-formed light By detecting the spot and determining the precision, if the precision is not satisfied, steps S5 to S7 are repeated, and when the precision is satisfied, the repeating step is stopped to complete the installation rotation correction.

7 is a theoretical calculation correction deviation curve in the x-direction and the y-direction of the galvanometer system in this embodiment, and FIG. 8 is the x-direction after calculating by substituting the known F-theta deviation value. And the theoretical correction deviation curve in the y direction, and FIG. 9 is the actual deviation diagram of the light spot in this embodiment, and as can be seen from the figure, after the adjustment of the correction, the light spot has a constant precision in the x direction and the y direction. It can be reached, and the actual precision must be set and corrected according to the actual case.

Preferably, the light spot position measuring device 7 is a profilometer; The galvanometer calibration system further includes a water cooling system 8 for performing water cooling for the galvanometer scanning system 1, wherein the water cooling temperature of the water cooling system 8 is 20 ° C to 24 ° C, and In the example, it is preferably 22 ° C.

In this embodiment, the galvanometer correction system further includes a work stage 9 that moves in the y direction, and implements the relative movement of the galvanometer scanning system 1 with respect to the workpiece on the work stage 9 in the y direction. You can. The optical spot position measuring device 7 is selectively connected to the upper or side part of the work stage 9, and when the optical spot position measuring device 7 is located on the side of the work stage 9, in FIG. As shown, not only can the calibration for the galvanometer system be implemented, but also does not affect the laser processing of the galvanometer scanning system 1 for the workpiece on the work stage 9 after the galvanometer calibration, Practicality is strong.

A plurality of galvanometer scanning systems 1 may be further installed in the gantry 4, and as shown in FIG. 10, a plurality of groups of galvanometer scanning systems 1 may be simultaneously processed, Here, the plurality of galvanometer scanning systems 1 may be connected to the same laser device 3, or may be respectively connected to the laser devices 3, similarly, different galvanometer scanning systems 1 are the same galvanometer It can be connected to the controller 2, it can be connected to each of the different galvanometer controller 2, it is adjusted according to the actual situation.

When calibrating for different types of galvanometer systems, select one of them from each type of galvanometer system to calibrate to obtain compensation data, and then obtain compensation data again to feed back to the galvanometer controller 2 Afterwards, it is only necessary to perform a direct verification on other galvanometer systems of the same type, thus significantly reducing the labor intensity and calibration time for calibrating the galvanometer during actual operation.

In conclusion, in the galvanometer calibration system and method provided in the present invention, when calibrating for a galvanometer scanning system, the galvanometer of the galvanometer scanning system is connected to the laser device at one or a plurality of specified measurement positions. The first corrected light spot and the second corrected light spot are formed using the deflection angles of the light source and the galvanometer emitted by the sensor, and the distance between the actual light spot position and the nominal position is calculated by calculating between the position and the nominal position of the formed light spot. Forms one real compensation relationship for, because it eliminates errors that exist in the process of artificially correcting and adjusting, and also has good adjustment effect, since each light spot is obtained after obtaining the average value of a plurality of light spots In addition, by reducing the accidental error further, the number of compensation amounts makes the actual light spot position closer to the nominal position. Can be done. The compensation amount is the compensation amount of the overall galvanometer scanning system, and after the compensation calculation is also performed for the rotation of the lens, through the third correction light spot and the fourth correction light spot, a more preferable compensation amount is obtained. Also, in the compensation calculation of the lens deflection, since the positions of the m light spots are averaged and then calculated between the nominal positions, an accidental error can be reduced.

The galvanometer scanning system raises the temperature during the working process and easily causes temperature drift, so that the light spot position measuring device, that is, the profilometer is not accurate in detecting the light spot, thus the galvanometer scanning system through the water cooling system After performing water cooling on the, the galvanometer scanning system can be maintained at a temperature suitable for detection, and in this embodiment, by taking 22 ° C., the error due to temperature drift is reduced to a minimum under the premise that the temperature is constant. Therefore, the calculation of the compensation amount can be made more accurate.

As described, each embodiment of the present specification is described in a gradual manner, and the parts focused on each embodiment are all different from other embodiments, and the same or similar parts between the respective embodiments are referred to each other. can do. In the case of the test method disclosed in the embodiment, since the test device used for this and a part of the device disclosed in the embodiment correspond to each other, the related test device is relatively briefly described, and the related part may refer to the device partial description. .

The above description is merely a description of a relatively preferred embodiment of the present invention, and is not any limitation on the scope of the present invention, and any modification made by a person skilled in the art according to the above disclosed contents , All the formulas fall within the protection scope of the claims.

1: Galvanometer scanning system 2: Galvanometer controller
3: Laser machine 4: Gantry
5: F-theta lens 6: Detection and sampling system
7: Optical spot position measuring device 8: Water cooling system
9: Work stage 10: 1st correction light spot
11: 2nd correction light spot 12: 3rd correction light spot
13: 4th correction light spot

Claims (13)

As a galvanometer correction system,
A galvanometer scanning system comprising a galvanometer; A galvanometer controller for controlling the movement of the galvanometer to implement a plurality of light spots in a field corresponding to the galvanometer; Gantry; A focusing device for focusing on the light flux emitted through the galvanometer; A detection and sampling system for implementing alignment between an optical spot position measuring device and the galvanometer; And a light spot position measuring device, wherein the galvanometer scanning system is capable of moving in a first horizontal direction along the gantry, and also in a vertical direction along the gantry. Correction system.
According to claim 1,
And a water cooling system for performing water cooling in the galvanometer scanning system.
According to claim 1,
The light spot position measuring device is a galvanometer calibration system, characterized in that the profilometer.
According to claim 1,
Further comprising a work stage that can move along the horizontal second direction, the second horizontal direction is perpendicular to the first horizontal direction, the light spot position measuring device is connected to the upper or side of the work stage Features a galvanometer calibration system.
According to claim 4,
The work stage is driven to move the light spot position measuring device to implement a measurement for the light spot position, characterized in that the galvanometer correction system.
According to claim 1,
Galvanometer calibration system, characterized in that a plurality of the galvanometer scanning system is installed in the gantry.
According to claim 1,
And a laser device for providing an incident luminous flux to the galvanometer scanning system.
According to claim 1,
The focusing device is a galvanometer correction system, characterized in that the F-theta lens.
A method for calibrating a galvanometer using the galvanometer correction system according to any one of claims 1 to 8,
A plurality of light spots in a field corresponding to the galvanometer by changing the swing angle of the galvanometer in the galvanometer scanning system so that the optical axis of the galvanometer moves along the first horizontal direction and the second horizontal direction, respectively. Forming, measuring and recording the positions of the plurality of light spots through an optical spot position measuring device;
Step S2 of acquiring an error parameter in a current galvanometer field by substituting data measured by the light spot position measuring device into an overlay model in a field;
Calculating an error amount in the galvanometer field to be compensated according to an error parameter in the current galvanometer field, wherein the error amount in the galvanometer field includes a first horizontal direction error amount and a second horizontal direction error amount. S3; And
Through the galvanometer controller, the galvanometer scanning system is corrected according to the first horizontal direction error amount and the second horizontal error amount obtained in step S3, and the corrected galvanometer scanning system is re-scanned. By controlling to re-form a plurality of light spots, and detecting the re-formed plurality of light spots and determining the precision, repeat steps S1 to S3 if the precision is not satisfied; And if the precision is satisfied, a step S4 of stopping the repetition step to complete error correction in the field.
The method of claim 9,
The in-field overlay model in step S2,
Δx = Mx · x-Ry · y + Tx
Δy = My · y + Rx · x + Ty,
Δx, Δy: represents the deviation between the actual imaging position of the light spot in the horizontal direction and the nominal position in the first horizontal direction and the second horizontal direction;
x, y: represents the nominal position of the light spot set by the galvanometer controller;
Tx, Ty: represents the parallel movement of the actual imaging position of the light spot in the galvanometer field and the nominal position in the first horizontal direction and the second horizontal direction;
Mx, My: represents the magnification of the actual image size of the light spot in the galvanometer field to the nominal image size of the light spot in the first horizontal direction and the second horizontal direction;
Rx, Ry: the actual imaging position and nominal position of the light spot in the galvanometer field indicate rotation in the first horizontal direction and the second horizontal direction;
In the test, a total of n = M × N light spots is measured, M and N are natural numbers, and for n light spots, the overlay model in the field is converted into a matrix form:

And
A method of calibrating a galvanometer characterized by fitting the least squares method to obtain errors Tx, Ty, Mx, My, Rx, Ry in the current galvanometer field.
The method of claim 10,
In step S3, the first horizontal error amount and the second horizontal error amount include a compensation amount of the optical axis of the galvanometer at the nominal position of each light spot,
DeltaX (y) = Δx-Tx-0.5 · (Rx + Ry) · y
DeltaY (x) = Δy-Ty-0.5 · (Rx + Ry) · x, galvanometer correction method characterized in that.
The method of claim 11,
The galvanometer scanning system performs a plurality of light spot position measurements at each specified measurement position, and takes an average value of a plurality of light spot position data and applies it to the calculation in step S3. Calibration method.
The method of claim 11,
The galvanometer scanning system maintains the position in the field of the optical axis of the galvanometer unchanged, the galvanometer scanning system performs the first horizontal movement in the gantry, and the galvanometer scanning system per stepping By projecting the light spot multiple times by, and using the light spot position measuring device, in the zero coordinate system of the gantry, the position of the light spot projected each time at each stepping position x _{i, j} , y _{i, j} Measured, i = 1,2, ..., n is the number of steps, j = 1,2, ... , m is the number of times the light spot is projected at each stepping position, step S5;
The position of the galvanometer scanning system is maintained to remain unchanged, and the optical axis of the galvanometer is performed along the first horizontal direction to perform light spot projection in the field at each measurement position, and the light spot position measurement device In the zero coordinate system of the gantry, the horizontal position x ′ _{i, j} , y ′ _{i, j} of each light spot projected at each measurement position is measured, but i = 1,2, ..., n Is the number of measurement positions, and j = 1,2, ... , m is the number of light spots projected at each measurement position, step S6;
In step S6, the nominal position of the light spot and the nominal position in step S5 are the same, respectively, x_nom _i , y_nom _i , and in step S5 and step S6, m exposure is performed at each position for the galvanometer scanning system. And the average value for the sampling data of the light spots of each part:

Seeking
Substituting the sampling data into the following formula to perform least square fitting to obtain the galvanometer installation rotation amount k,

In the above formula, b is a constant step S7; And
Through the galvanometer controller, the galvanometer scanning system is corrected according to the amount of rotation of the galvanometer installed in step S7, and the corrected galvanometer scanning system is re-scanned to control a plurality of light spots to be re-formed. In addition, by detecting and recognizing a plurality of re-formed light spots to determine the precision, if the precision is not satisfied, repeat steps S5 to S7, and if the precision is satisfied, repeat the step S8 to complete the installation rotation correction by stopping the repeating step. Galvanometer calibration method characterized in that it further comprises.

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